This invention relates to a food processing machinery and particularly an extrusion apparatus for processing food.
Various types of food processing machinery are available on the market for producing different types of food. FIG. 1 illustrates a commonly used extrusion apparatus 2 for producing dough. It has a funnel 1 at the top for holding dough to be processed and a plurality of rollers 4 located below the funnel 1 to form a squeezing space 2. The rollers 4 are driven by a motor to squeeze the dough dropping down from the funnel 1. The squeezed dough is carried away by a conveyer located below the rollers 4. The rollers 4 usually are formed in cylindrical shapes and have smooth peripheral surfaces. The dough held in the squeezing space is being extruded between the rollers by constant and even force and lots of air is squeezed out of dough. The resulting squeezed dough becomes a relatively hard slat with little resilience. Food produced by such a dough do not have desirable taste. There is still rooms for improvement.